The objectives of the proposed studies are to gain insight into the mechanisms involved in the control and integration of the primate hypothalamic-pituitary-target tissue axes during intrauterine life and infancy. For studies in utero, a chronically catheterized fetal monkey will be employed. Endocrine regulation of the pituitary-adrenal and pituitary-gonadal systems will be studied. Studies also will be performed concerning maturation and changing sensitivity of the pituitary-adrenal and pituitary-gonadal systems in the fetal and infant monkey and the factors modulating these changes.